runtime: fix argument dump in traceback
runtime: fix argument dump in traceback

Was printing words at SP instead of at FP
after shuffle due to nascent flag.

R=r, r2
CC=golang-dev
http://codereview.appspot.com/2316044

ssrl/go,h8liu/golang,apparentlymart/golang,dsriram/golang,gnanderson/go,apparentlymart/golang,h8liu/golang,apparentlymart/golang,pombredanne/go-deleteme,h8liu/golang,ssrl/go,apparentlymart/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,dsriram/golang,ssrl/go,ssrl/go,ssrl/go,tv42/old-go,gnanderson/go,gnanderson/go,gnanderson/go,ssrl/go,pombredanne/go-deleteme,gnanderson/go,apparentlymart/golang,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,dsriram/golang,apparentlymart/golang,dsriram/golang,gnanderson/go,tv42/old-go,apparentlymart/golang,dsriram/golang,ssrl/go,pombredanne/go-deleteme,gnanderson/go,tv42/old-go,pombredanne/go-deleteme,dsriram/golang,tv42/old-go,pombredanne/go-deleteme